The present invention relates to sailing vessels; and more particularly it relates to sailing vessels of the catamaran type, which are characterized as having two laterally spaced hulls. In a catamaran, the hulls may be spaced apart by a rigid framework which also supports a trampoline on which the occupants sit or lie. This framework also supports the mast and boom. The framework is conventionally made of hollow aluminum tubes, and it is secured at each side to the associated hull at forward and rear locations by means of upright tubular members, called "pylons" which are embedded in the hull. These pylons are substantially cylindrical, although they actually have a greater fore-to-aft dimension in cross section, thereby providing a teardrop shape.
Each of the hulls is provided with a deck for covering the same, and each hull is secured to its associated deck by means of an upper glue seam extending throughout conforming portions on the periphery of the deck. Not only is a pylon secured to a hull, but it is also rigidly secured to the deck through which it passes.
In the past, pylons have been cut to length and first rigidly secured to a deck. A "shoe" is inserted in the hull for each pylon, and the deck/pylon sub-assembly is then assembled to a hull by inserting the pylons in their respective shoes and clamping the hull to the pylon along the glue seam.
A problem has arisen in this method of construction, and it concerns the tolerances in the length of the pylon, together with the particular deck/hull fit. If the pylon is too long, when the deck is clamped to the hull, the pylon will bear on the shoe and cause it to deform or form a "print" on the hull. It will also exert a force tending to part the deck and hull along the glue seam after the hull is removed from the glue jig. Further, because the pylon is a hollow tube, much of the glue originally in the well simply fills the cavity in the pylon so as to not perform its function of securing the outer surface of the pylon to the well of the shoe. If, on the other hand the pylon is too short for a particular deck/hull combination, then it will not exert sufficient force on the shoe to insure rigid attachment of the shoe to the hull, such force being necessary during the setting or drying of the glue.
According to the present invention, a cylindrical core or plug of semi-rigid plastic foam is placed telescopically into the distal end of the pylon, where it is held by friction enhanced and by means of internally projecting rivets securing a pylon strap to the pylon for additional holding power. The foam core extends partially out from the distal end of the pylon prior to assembly with the shoe.
After glue is placed in the well of the shoe, the deck and pylon are assembled to the hull. When the deck is clamped to the hull, the foam core is urged upwardly into the hollow pylon to the extent necessary to exactly compensate for the proper glue seam between deck and hull. The internal projection of the rivets offer proper resistance to insertion of the foam core so that the glue in the well is displaced upwardly about the outer surface of the pylon as it is inserted, thereby insuring a strong bond between pylon and shoe. Further, because of the resistance to insertion of the foam core into the pylon during assembly, a force is applied to the shoe to urge it against the hull, but it is not an excessive force so that there is no bulge or printing on the exterior of the hull. Thus, the pylons can be cut somewhat shorter than heretofore, and the length of the pylon is not a critical element in pylon/shoe, shoe/hull or hull/deck bonding, as it had been in the past.
Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.